1. Field of the Invention
The present invention relates to a resin composition to be used as a material for an optical waveguide component, and to an optical waveguide produced by employing the resin composition. The resin composition for the optical waveguide is excellent in flexibility and moisture absorption resistance. The optical waveguide produced by employing the resin composition is used, for example, for mobile devices such as mobile phones.
2. Description of the Related Art
Optical waveguides are generally incorporated in optical devices such as optical waveguide devices, optical integrated circuits and optical wiring boards, and widely used in optical communications, optical information processing and other general optics. Such an optical waveguide typically includes a core provided as a light passage in a predetermined pattern, and an under-cladding layer and an over-cladding layer covering the core.
Various types of materials are used for forming the core, the under-cladding layer and the over-cladding layer in predetermined patterns. For example, a specific carboxyl-containing epoxy compound, which is photo-cationically polymerizable or curable, is used as a material for the cladding layers of the optical waveguide (see, for example, JP-A-2003-147045).
Where the optical waveguide is routed through a hinge portion of a foldable mobile phone, for example, the optical waveguide is required to have bendability or flexibility. For improvement of the flexibility of the optical waveguide, a resin composition containing the epoxy compound disclosed in JP-A-2003-147045 is used as a material for at lest one of the cladding layers and the core of the optical waveguide.
Where the resin composition disclosed in JP-A-2003-147045 is used as the material for any of the aforementioned optical waveguide components, however, the resulting optical waveguide indeed has sufficient flexibility, but is highly hygroscopic. If the optical waveguide components are composed of the highly hygroscopic material, the refractive indexes of the optical waveguide components will vary due to moisture absorption, resulting in greater light loss. This reduces the reliability.
In view of the foregoing, it is an object of the present invention to provide a resin composition which is excellent in flexibility and moisture absorption resistance and has a lower viscosity for use as a material for an optical waveguide, and to provide an optical waveguide produced by employing the resin composition.